Procedures for operating in long term evolution idle mode

ABSTRACT

Various apparatuses and procedures for applying cell reselection priorities in a wireless transmit/receive unit (WTRU) are described. A method includes receiving a message including first cell reselection priorities assigned to a first plurality of frequencies and a validity timer associated with the first cell reselection priorities, where the validity timer indicates a length of time the first cell reselection priorities are valid, starting the validly timer based on the received message, performing a cell reselection evaluation using the first cell reselection priorities, and, on a condition that the validity timer expires, deleting the first cell reselection priorities, applying second cell reselection priorities assigned to a second plurality of frequencies, and performing a cell reselection evaluation using the second cell reselection priorities.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/720,144 filed May 22, 2015, which is a continuation of U.S. patentapplication Ser. No. 12/505,031 filed Jul, 17, 2009, which issued asU.S. Pat. No. 9,042,883 on May 26, 2015 which claims the benefit of U.S.Provisional Application Ser. No. 61/086,674, filed Aug. 6, 2008, thecontents of which are hereby incorporated by reference herein.

FIELD

This application is related to wireless communications.

BACKGROUND

In the Third Generation Partnership (3GPP) long term evolution (LTE),measurements take the wireless transmit/receive unit (WTRU) mobilitystate into account. For example, whether a WTRU is moving with low orzero speed has a different effect on the measurements than a WTRU movingwith high speed on a rural area or a highway due to the Doppler Effectin the radio transmission and reception. Therefore in LTE, differentscaling factors for measurements apply to the WTRU in different mobilitystates to balance or normalize the Doppler Effects on different mobilityspeeds. How to maintain the WTRU mobility states between Idle mode andConnected mode is not specified.

In LTE, the WTRU has three mobility states: low mobility, mediummobility, and high mobility. In Idle mode, when the WTRU does not have acall, it counts the number of reselections. In Connected mode, when theWTRU has a call, it counts the number of handovers. The WTRU counts thenumber of reselections or the number of handovers and determines whetherit is not moving (also called stationary), it is moving slow (alsocalled normal mobility), or it is moving fast (also called highmobility). Reselections and handovers are treated differently becausethe time needed to reselect is different from the time needed to performa handover. The mobility states cannot be carried over from Idle mode toConnected mode for most purposes. A mechanism of adapting the mobilitystate when the WTRU transitions from Idle mode to Connected mode isneeded. Also, the mobility state between modes should not be lost,meaning if the WTRU is moving fast while in Idle mode, and thentransitions to Connected mode, the WTRU should not have to restart themobility state determination. For example, if the WTRU is moving fast(i.e., in the high mobility state) it has an impact on how the WTRUperforms reselections and handovers.

When the WTRU attempts to reselect to another cell, it needs to makesure that the target cell satisfies the minimum signal level, signalstrength, and condition. The WTRU compares this data with someparameters that are transmitted by the network. That comparison isembodied in an equation called the S criteria. The S criteriaeffectively says how strong or weak the target cell is. If the Scriteria, which is the difference between the signal strength and thethreshold signaled by the network, is below zero, then the WTRU does nothave to consider the target cell. If the S criteria is above zero, thenthe WTRU may proceed to camp on the target cell. The S criteria meansthat the signal strength of the target cell has to absolutely meet atleast a minimum threshold, below which the network thinks that thetarget cell is not worth camping on. The LTE WTRU cell selection andreselection basic rules have the WTRU check the serving cell or anothercell's signal strength using the S criteria. In LTE, one component inthe S criteria, i.e., the Pcompensation parameter, remains undefined andneeds to be specified.

LTE includes the concept of priority in cell reselection, which meansthat there are certain frequencies, for example, UMTS or GSM, that aregiven a priority. The WTRU has to follow the priority, so, for example,frequency “a” may be given priority one, frequency “b” may be givenpriority two, or vise versa. The WTRU has to make sure that it firsttries to camp on frequency “a,” and if it cannot find the cell offrequency “a,” then it goes to frequency “b.” Currently, in thestandards, there is no clear indication how long these priorities arevalid. The WTRU may be signaled a priority using system information ordedicated RRC messages. But when the WTRU considers the priorities to nolonger be valid or expired is not described.

In UMTS systems, there is a parameter called Pcompensation, whichcompensates for the pathloss when a WTRU performs cell reselection.There is no clear indication in LTE to date of how the Pcompensationparameter is going to be designed. This disclosure proposes somedefinitions of Pcompensation.

SUMMARY

Various procedures for operating a wireless transmit/receive unit (WTRU)in LTE Idle mode are described.

According to an example, a method includes receiving a message includingfirst cell reselection priorities assigned to a first plurality offrequencies and a validity timer associated with the first cellreselection priorities, where the validity timer indicates a length oftime the first cell reselection priorities are valid, starting thevalidly timer based on the received message, performing a cellreselection evaluation using the first cell reselection priorities, and,on a condition that the validity timer expires, deleting the first cellreselection priorities, applying second cell reselection prioritiesassigned to a second plurality of frequencies, and performing a cellreselection evaluation using the second cell reselection priorities.

According to another example, a WTRU includes a receiver and a processorconfigured to receive a message including first cell reselectionpriorities assigned to a first plurality of frequencies and a validitytimer associated with the first cell reselection priorities, where thevalidity timer indicates a length of time the first cell reselectionpriorities are valid; the processor is further configured to start thevalidity timer in response to the received message; the processor isfurther configured to perform a cell reselection evaluation using thefirst cell reselection priorities; and the processor is furtherconfigured, on a condition that the validity timer expires, to deletethe first cell reselection priorities, apply second cell reselectionpriorities assigned to a second plurality of frequencies, and perform acell reselection evaluation using the second cell reselection priorities

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawings,wherein:

FIG. 1 shows an example wireless communication system including aplurality of wireless transmit/receive units (WTRUs) and an evolved NodeB (eNB);

FIG. 2 is an example functional block diagram of one WTRU and the eNB ofFIG. 1;

FIG. 3 is a flowchart of a method for updating cell reselection priorityinformation;

FIG. 4 is a flowchart of a method for updating cell reselection priorityinformation in connection with a timer;

FIG. 5 is a flowchart of a method for converting the WTRU's mobilitystate when the WTRU changes RRC modes; and

FIG. 6 is a flowchart of a method for assigning the WTRU's mobilitystate by the network when the WTRU changes RRC modes.

DETAILED DESCRIPTION

When referred to hereafter, the term “wireless transmit/receive unit(WTRU)” includes, but is not limited to, a user equipment (UE), a mobilestation, a fixed or mobile subscriber unit, a pager, a cellulartelephone, a personal digital assistant (PDA), a computer, or any othertype of user device capable of operating in a wireless environment. Whenreferred to hereafter, the term “base station” includes, but is notlimited to, a Node B, an evolved Node B (eNB), a site controller, anaccess point (AP), or any other type of interfacing device capable ofoperating in a wireless environment.

FIG. 1 shows an example wireless communication system 100 including aplurality of WTRUs 110 and an eNB 120. As shown in FIG. 1, the WTRUs 110are in communication with the eNB 120. It should be noted that, althoughan example configuration of WTRUs 110 and an eNB 120 is depicted in FIG.1, any combination of wireless and wired devices may be included in thewireless communication system 100.

FIG. 2 is an example functional block diagram 200 of one WTRU 110 andthe eNB 120 of the wireless communication system 100 of FIG. 1. As shownin FIG. 2, the WTRU 110 is in communication with the eNB 120.

In addition to the components that may be found in a typical WTRU, theWTRU 110 includes a processor 112, a receiver 114, a transmitter 116,and an antenna 118. The receiver 114 and the transmitter 116 are incommunication with the processor 112. The antenna 118 is incommunication with both the receiver 114 and the transmitter 116 tofacilitate the transmission and reception of wireless data. Theprocessor 112 is configured to determine the LTE mobility state of theWTRU, determine cell reselection criteria, determine cell reselectionpriority validity, and determine a CSG cell coverage extension.

In addition to the components that may be found in a typical eNB, theeNB 120 includes a processor 122, a receiver 124, a transmitter 126, andan antenna 128. The receiver 124 and the transmitter 126 are incommunication with the processor 122. The antenna 128 is incommunication with both the receiver 124 and the transmitter 126 tofacilitate the transmission and reception of wireless data. Theprocessor 122 is configured to determine the LTE mobility state of theWTRU, determine cell reselection criteria, determine cell reselectionpriority validity, and determine a CSG cell coverage extension.

Validity Lifetime for LTE Reselection Priorities

The WTRU may use one or more of the following conditions to maintain itsreselection priorities. In all the conditions listed below, the WTRU'salready present priorities may be overwritten when new priorities aresignaled by the network.

(1) WTRU power-on/WTRU power-off. In this case, once the WTRU receivesthe cell reselection priorities, they are retained until the WTRU isturned off or until the cell reselection priorities are overwritten bythe network.

(2) Next system information (SI) update. The WTRU may maintain its cellreselection priorities until the next SI update. When the SI changes,the WTRU re-reads the SI and updates the cell reselection priorities.There might be certain conditions when the WTRU does not update the cellreselection priorities based on the new SI. For example, if the WTRUalready has dedicated cell reselection priorities, then it might notoverride the cell reselection priorities provided by the SI.

In general, the cell reselection priority information provided by the SIis broadcast, so all WTRUs receive the same cell reselection priorityinformation. Dedicated cell reselection priorities are sent to a givenWTRU. So if a WTRU has dedicated cell reselection priorities, in thenext SI update when the SI changes, the WTRU might not override thededicated cell reselection priorities with the cell reselectionpriorities from the SI.

FIG. 3 is a flowchart of a method 300 for updating cell reselectionpriority information. The method begins with the WTRU applying existingcell reselection priorities (step 302). A determination is made whetherthe WTRU received dedicated cell reselection priorities (step 304). Ifthe WTRU has received dedicated cell reselection priorities, then theWTRU applies the dedicated cell reselection priorities, overwriting theexisting cell reselection priorities (step 306).

The WTRU may also receive timer information with the dedicated cellreselection priorities, to indicate the length of time that thededicated cell reselection priorities are valid. If the WTRU does notreceive timer information for the dedicated cell reselection priorities(step 308), then the method terminates (step 310). If the WTRU receivestimer information for the dedicated cell reselection priorities (step308), the timer is started (step 312). When the timer expires (step314), this means that the dedicated cell reselection priorities are nolonger valid.

If the WTRU has not received any dedicated cell reselection priorities(step 304) or if the timer has expired (step 314), then the WTRU waitsto receive a SI update (step 316). After receiving the SI update, theWTRU overwrites the existing cell reselection priorities withinformation contained in the SI update (step 318) and the methodterminates (step 310).

(3) Timer information. Along with the cell reselection prioritiessignaled to the WTRU, an optional parameter called validity time isdefined, which tells the WTRU how long it may retain the cellreselection priorities. When the timer expires, the cell reselectionpriority information is discarded. In one embodiment, the timer onlyapplies to dedicated cell reselection priorities received by the WTRU.In another embodiment, the timer is started when the WTRU enters theConnected mode.

When the timer expires, the WTRU re-reads the SI or requests the networkto provide new cell reselection priorities. Alternatively, once thetimer expires, the WTRU waits for the next available SI readingopportunity to update its cell reselection priorities. While thevalidity timer is running, the WTRU's cell reselection priorities may beoverwritten if the WTRU receives dedicated cell reselection priorities.

FIG. 4 is a flowchart of a method 400 for updating cell reselectionpriority information in connection with a timer. The method begins withthe WTRU receiving cell reselection priorities (step 402). The WTRU alsoreceives timer information (step 404) and starts a timer based on thisinformation (step 406). A determination is made whether the timer hasexpired (step 408). If the timer has expired, then the WTRU has one ofthree options: the WTRU re-reads the SI immediately (step 410), the WTRUwaits for the next regular opportunity to read the SI (step 412), or theWTRU requests new cell reselection priority information from the network(step 414). After the WTRU has received the new cell reselectionpriority information, it applies the new cell reselection priorityinformation (step 416) and the method terminates (step 418).

If the timer has not expired (step 408), a determination is made whetherthe WTRU has received dedicated cell reselection priorities (step 420).If the timer has not expired, the WTRU waits until the timer has expired(step 408) or the WTRU receives dedicated cell reselection priorities(step 420). If the WTRU has received dedicated cell reselectionpriorities (step 420), then it applies the new cell reselection priorityinformation (step 422) and resets the timer (step 424).

(4) Scope of cell reselection priorities. The scope of the cellreselection priorities may be defined as a simple variable with a fewenumerated values. For example, the enumerated values may include: (a)only valid within a public land mobile network (PLMN) or (b) validacross many PLMNs. As another example, the enumerated values mayinclude: (a) only valid within a Tracking Area, (b) valid across manyTracking Areas, (c) only valid within one LTE frequency layer, or (d)valid within several LTE frequency layer(s) (multicast-broadcast singlefrequency network (MBSFN) or not). The definition of the scope of thecell reselection priorities includes information for the WTRU to knowwhen to read the new cell reselection priorities.

(5) RRC message forcing the WTRU to read the system information blocks(SIBs). The WTRU may be forced to read the SIBs to obtain new cellreselection priority information by using RRC messages. Existing RRCmessages may also be used to force the WTRU to update its cellreselection priority information. For example, when the WTRU goes intoIdle mode, the RRC connection release or reject message may include asimple enumerated information element (IE) which may force the WTRU toread the SIBs.

In one embodiment, if the WTRU is in Idle mode and the SI changes, thenetwork may send a new RRC message, like a paging message, to the WTRUto force the WTRU to read the SIBs to obtain the new SI. One reason thatthe SI may change is if the cell reselection priorities change; however,the SI may change for any reason.

Mobility state handling between Idle mode and Connected mode

There are three mobility states defined in LTE: the normal state, themedium state, and the high state. In the current 3GPP LTE specification(TS 36.304), the LTE WTRU mobility state in Idle mode is determinedbased on a number of cell reselections experienced during a time periodT_(CRmax) and a comparison to the threshold values N_(CR) _(_) _(H) andN_(CR) _(_) _(M). In Connected mode, a number of handovers is used as acriteria for mobility.

Given the above conditions, to retain or maintain the mobility statebetween the Idle mode and the Connected mode, a relationship between themobility states and their quantifying/qualifying parameters is proposed.For example, X number of cell reselections in Idle mode may map to Ynumber of handovers in Connected mode or vice versa. Mapping the numberof cell reselections to the number of handovers or the number ofhandovers to the number of cell reselections may reflect thegeographical cell size.

Convert the mobility state directly between the LTE WTRU modes

Several rules for defining a direct mapping for the WTRU mobility statebetween Idle mode and Connected mode are proposed.

(1) Symmetric same state direct mapping. In general, state A in Idlemode maps to state A in Connected mode. For example, the Idle modenormal state maps to the Connected mode normal state, the Idle modemedium state maps to the Connected mode medium state, and the Idle modehigh state maps to the Connected mode high state. This approach might beuseful because when the WTRU changes modes (Idle to Connected orConnected to Idle), the WTRU's moving speed remains the same.

(2) Asymmetric state direct mapping. In general, state A in Idle modemaps to state B in Connected mode or vice versa. For example, the Idlemode normal state maps to the Connected mode medium state, the Idle modemedium state and high state both map to the Connected mode high state.The latter mapping assumes that the measurement requirement is stricterin the Connected mode, thus converting a low mobility state in the Idlemode to a higher mobility state in the Connected mode. If themeasurement requirement is stricter in the Idle mode, a higher mobilitystate in the Connected mode may be mapped to a lower mobility state inthe Idle mode, e.g., the Connected mode normal state maps to the Idlemode medium state, the Connected mode medium state and high state bothmap to the Idle mode high state, etc.

(3) Reset the mobility state. Alternatively, the WTRU may reset itsmobility state to the stationary or normal mobility state when itchanges modes, irrespective of the WTRU's mobility state in the previousmode.

FIG. 5 is a flowchart of a method 500 for converting the WTRU's mobilitystate when the WTRU changes RRC modes. The method 500 begins with theWTRU operating in a mobility state in an RRC mode (step 502). Forexample, the WTRU may be operating in the low mobility state while inIdle mode. The WTRU changes RRC modes, for example from Idle mode toConnected mode (step 504). The WTRU's mobility state may be mappedbetween the two RRC modes (step 506) or the mobility state may be resetupon changing RRC modes (step 508). The new mobility state is applied tothe current RRC mode (step 510) and the method terminates (step 512).

Inherit the Mobility State and Adjust the State During WTRU Mode Change

This method proposes that when the WTRU changes RRC operating modes(i.e., between Idle mode and Connected mode), the mobility state ishandled as follows.

(1) Inherit the mobility state initially when the RRC mode changes.

(2) Adjust the mobility state in the next short period with theinherited parameter values in the old mode (e.g., Idle mode) toparameter values in the new mode (e.g., Connected mode) according to thefollowing conversions. The “short period” is a predefined period of timein which the WTRU needs to finish converting the parameter valuesbetween RRC modes. The short period may be known to the WTRU or may besignaled to the WTRU by the network.

(a) Define system-configurable conversion factors (one for allparameters or one for each parameter) to convert the mobility stateparameters from one RRC mode to the other for: the state thresholds(i.e., N_(CR) _(_) _(H) or N_(CR) _(_) _(M) to the comparable handover(HO) thresholds), the time periods, and the current cell reselection(CR) or HO count. As an example, employing the conversion factorsFAC_(CR) _(_) _(HO) _(_) _(H) and FAC_(CR) _(_) _(HO) _(_) _(M) to scalethe N_(CR) _(_) _(H) and the N_(CR) _(_) _(M) thresholds (the variablesfor HO may be N_(HO) _(_) _(H) and N_(HO) _(_) _(M)) with respect to CRand HO, such that

N _(CR) _(_) _(H)=FAC_(CR) _(_) _(HO) _(_) _(H) ×N _(HO) _(_) _(H)  Equation (1)

N _(CR) _(_) _(M)=FAC_(CR) _(_) _(HO) _(_) _(M) ×N _(HO) _(_) _(M)  Equation (2)

The factor FAC_(T) _(_) _(CR) _(_) _(Ho) may be used to convertT_(maxHyst) between CR and

HO.

T _(maxHyst-CR)=FAC_(T) _(_) _(CR) _(_) _(HO) ×T _(maxHyst-HO)  Equation (3)

(b) Alternatively, maintain the state thresholds and the time period,but convert the counts between the CR and HO. Therefore, a conversionfactor (FAC_(CR) _(_) _(HO) _(_) _(COUNT)) is needed when the WTRU's RRCmode changes (from Idle mode to Connected mode or vise versa). Forexample, the counts before the state change are Count_(HO) andCount_(CR), respectively. When the state changes, the scale factorFAC_(CR) _(_) _(HO) _(_) _(COUNT) is applied to convert the values.

Count_(HO)=Count_(HO)×FAC_(CR) _(_) _(HO) _(_) _(COUNT)   Equation (4)

Count_(CR)=Count_(CR)×FAC_(CR) _(_) _(HO) _(_) _(COUNT)   Equation (5)

The resulting new scaled counts may be used to compare to the unchangedthreshold values in the new state. For example, the scaled Count_(CR) iscompared with the unsealed N_(CR—)H threshold.

Network-Based Mobility State Assignments

Based on the detected or reported WTRU mobility state, the network mayassign a mobility state for the WTRU when the RRC mode changes. Theassigned mobility state may be temporary and may be adjusted later usingnew parameters.

(1) The WTRU reports its mobility state by sending a RRC message. TheWTRU retains its current mobility state for a predetermined period oftime or the WTRU adjusts its mobility state during this period using oneof the methods described above. One of the existing RRC messages (forexample, RRC-Connection-Req or RRC-Re-Establishment-Req) may be used orother new or existing RRC messages may be defined or modified for thispurpose. The WTRU reports its mobility state when it changes RRC modes.

(2) The network then assigns or informs the WTRU of its mobility stateby another RRC message (for example, RRC-Connection-Setup,Re-Establishment-Resp, HO-Command, RRC-Connection-Release, or any otherdefined or modified RRC message).

(3) A RRC message may be defined so that when the WTRU has established aconnection with the network, it sends a mobility state request messagewith the mobility state calculated from the Idle mode. The network sendsback a mobility state confirm message with the mobility state it thinksthe WTRU should have. During this period, the WTRU may not have toperform any mobility calculations.

FIG. 6 is a flowchart of a method 600 for assigning the WTRU's mobilitystate by the network when the WTRU changes RRC modes. The method 600begins with the WTRU operating in a mobility state in an RRC mode (step602). For example, the WTRU may be operating in the low mobility statewhile in Idle mode. The WTRU changes RRC modes, for example from Idlemode to Connected mode (step 604).

The WTRU reports its current mobility state to the network (step 606).Optionally, the WTRU may request that the network assign it a newmobility state (step 608). The WTRU receives a new mobility state (step610), either upon the network's initiation or in response to a requestfrom the WTRU. The new mobility state is applied to the current RRC mode(step 612) and the method terminates (step 614).

S Criteria Pcompensation

The cell selection criterion S is fulfilled when:

Srxlev>0   Equation (6)

where

Srxlev=Q _(rxlevmeas)−(Q _(rxlevmin) −Q _(rxlevminoffset))−Pcompensation  Equation (7)

where Srxlev is the cell selection received signal level value in dB,Q_(rxlevmeas) is the measured cell received signal level value (RSRP),Q_(rxlevmin) is the minimum required received signal level in the cell(in dBm), and Q_(rxlevminoffset) is only applied when a cell isevaluated for cell selection as a result of a periodic search for ahigher priority PLMN while camped normally in a visited PLMN.

In UMTS, the Pcompensation parameter (which may be defined as, forexample, max(UE_TXPWR_MAX_RACH−P_MAX, 0)) is used to take the uplinkinterference into account for the cell measurement. In UMTS, each WTRU'suplink power is another WTRU's interference. When the maximum alloweduplink transmit power (UE_TXPWR_MAX_RACH) is high, it implies that theuplink interference is also high. Therefore, it presents as anunfavorable factor to the S criteria in terms of cell selection or cellreselection (i.e., Q_(rxlevmeas) needs to be stronger to fulfill the Scriteria).

In LTE, the intra-cell interference between sub-carriers is supposedlynone or very low. Thus, the interference between WTRUs in terms ofuplink RACH is assumed (in this case) to be small to negligible. Thefollowing options are proposed.

(1) Remove the Pcompensation term from the equation such that

Srxlev=Q _(rxlevmeas)−(Q _(rxlevmin) −Q _(rxlevminoffset))   Equation(8)

The value of Q_(rxlevminoffset) should already compensate for the valueof

Pcompensation, meaning that Q_(rxlevminoffset) may be defined so thatPcompensation is not needed.

(2) Allow the Pcompensation term in Equation (7) to affect the Srxlev inboth ways, i.e., require Q_(rxlevmeas) to be stronger or weaker tofulfill the S criteria. Set Pcompensation=(UE_TXPWR_MAX_RACH−P_MAX).Consequently, if the system published UE_TXPWR_MAX_RACH is greater thanthe WTRU's P_MAX, Pcompensation is positive, requiring Q_(rxlevmeas) tobe higher to meet the condition Srxlev>0. If UE_TXPWR_MAX_RACH issmaller than the WTRU's P_MAX, Pcompensation is negative, requiringQ_(rxlevmeas) to be lower to meet the condition Srxlev>0 (as opposed toin UMTS, where Pcompensation=max(UE_TXPWR_MAX_RACH−P_MAX, 0)). Thismeans that when UE_TXPWR_MAX_RACH is smaller than the WTRU's P_MAX,Pcompensation is 0, thereby not contributing to the equation.

(3) Another option for Pcompensation is to tie the uplink compensationwith the pathloss (the distance from the eNB, i.e., thepathloss=CELL_TX_POWER−Q_(rxlevmeas)) that the WTRU measures in the LTEcell. So the greater the value of the pathloss, the stronger or weakeris the compensation to the S criteria. For the Srxlev formula inEquation (7), Pcompensation =compensate (pathloss, network or systemdefined comp-value-table), where compensate may be any functionreturning the compensation value based on the current WTRU pathloss andthe network defined compensation vectors.

Two examples on the pathloss to compensation value mapping are asfollows.

(a) The Pcompensation value results from a function of the pathlossvalue.

Pcompensation=(a×pathloss)+b   Equation (9)

where a is a scaling factor and b is an offset. Both a and b may be anypositive or negative numbers, fractions, or 0. It is noted that this maybe linear (i.e., a and b are consistently one value throughout) ordiscrete, applying to ranges of measured pathloss. For example, forpathloss measurements between 30 and 40 dBs, a is ⅔ and b is 4, whilefor pathloss measurements between 40 and 50 dBs, a is 3/4 and b is 5,and so on.

The pathloss value is based on the current measurement (i.e., togetherwith the Q_(rxlevmeas), say the nth) or the previous measurement (saythe n−1^(th)) to smooth out the possible jittering. The values of a andb may be signaled to the WTRU through RRC signaling, SIB signaling, maybe predefined in the specification, or the WTRU may be preconfiguredwith the values.

(b) The Pcompensation value is obtained from a standards-defined ornetwork-published (via SI) mapping table, such as:

Pathloss Pcompensation in dB in dB 30 3 31 3.1 32 3.2 — — 150 9Other values or tables may also be used.

Coverage Extension Subscription

Closed subscriber group (CSG) coverage extension means that if a CSGcell may be used to extend the coverage of the macro cell, then the CSGcell may be put in a particular place to provide service in areas wherethe macro cell is not able to provide service. A network operator maydeploy CSG cells for coverage extension purposes. Some users maysubscribe to this service and others may not.

The WTRU may have a configurable parameter (e.g., one bit) thatrepresents the subscription status of the user/WTRU to these services.At least one of non-access stratum (NAS), RRC, or Open Mobile Alliance(OMA) Device Management signaling may be used by the network toconfigure this parameter. This parameter may be stored in the WTRU innon-volatile memory, in an application on the Universal IntegratedCircuit Card (UICC) (e.g., Universal Subscriber Identity Module (USIM)or LTE equivalent), or in some other place within the WTRU (e.g.,Read-Only Memory).

The WTRU may use the coverage extension parameter to determine whetherit has access to a coverage extension CSG cell (this may also bereferred to as a hybrid cell). A WTRU that detects (in Idle mode or inConnected mode) a coverage extension CSG cell may determine that it hasaccess to that CSG cell if the coverage extension parameter within theWTRU indicates a valid subscription (e.g., by the bit being set) tocoverage extension services. The WTRU may detect that a cell is acoverage extension CSG cell using at least one of the following.

(1) The one bit CSG indicator on the system information (e.g., SIB1)being set to true.

(2) A Physical Cell ID corresponding to a CSG cell.

(3) An indicator on the broadcast channel (e.g., one bit) on the systeminformation (e.g., SIB1) indicating that the cell is for coverageextension (e.g., a one bit indicator or a public/private CSG cellindicator). The coverage extension indicator may be an optional bit, mayonly be present only if the CSG indicator is set to “True,” or may bemandatory.

(4) A Physical Cell ID corresponding to a coverage extension CSG cell.

A WTRU with a valid coverage extension CSG cell would not have to verifythe presence of the CSG ID of the coverage extension CSG cell in itswhite list to confirm accessibility and would be able toselect/reselect/handover to such a coverage extension CSG cell withoutverifying the CSG ID on its white list. A WTRU with a valid coverageextension subscription may automatically add the CSG IDs of accessiblecoverage extension CSG cells to its white list.

A WTRU without a valid coverage extension subscription (indicated by acertain value of the configurable parameter, e.g., the bit not beingset) would not be able to access a coverage extension CSG cell. Such aWTRU may, however, have access to this cell if the CSG ID of thecoverage extension CSG cell was programmed in its white list.

Although features and elements are described above in particularcombinations, each feature or element may be used alone without theother features and elements or in various combinations with or withoutother features and elements. The methods or flow charts provided hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable storage medium for execution by ageneral purpose computer or a processor. Examples of computer-readablestorage mediums include a read only memory (ROM), a random access memory(RAM), a register, cache memory, semiconductor memory devices, magneticmedia such as internal hard disks and removable disks, magneto-opticalmedia, and optical media such as CD-ROM disks, and digital versatiledisks (DVDs).

Suitable processors include, by way of example, a general purposeprocessor, a special purpose processor, a conventional processor, adigital signal processor (DSP), a plurality of microprocessors, one ormore microprocessors in association with a DSP core, a controller, amicrocontroller, Application Specific Integrated Circuits (ASICs), FieldProgrammable Gate Arrays (FPGAs) circuits, any other type of integratedcircuit (IC), and/or a state machine.

A processor in association with software may be used to implement aradio frequency transceiver for use in a wireless transmit receive unit(WTRU), user equipment (UE), terminal, base station, radio networkcontroller (RNC), or any host computer. The WTRU may be used inconjunction with modules, implemented in hardware and/or software, suchas a camera, a video camera module, a videophone, a speakerphone, avibration device, a speaker, a microphone, a television transceiver, ahands free headset, a keyboard, a Bluetooth® module, a frequencymodulated (FM) radio unit, a liquid crystal display (LCD) display unit,an organic light-emitting diode (OLED) display unit, a digital musicplayer, a media player, a video game player module, an Internet browser,and/or any wireless local area network (WLAN) or Ultra Wide Band (UWB)module.

What is claimed is:
 1. A method for applying cell reselection prioritiesin a wireless transmit/receive unit (WTRU), comprising: receiving amessage including first cell reselection priorities assigned to a firstplurality of frequencies and a validity timer associated with the firstcell reselection priorities, wherein the validity timer indicates alength of time the first cell reselection priorities are valid; startingthe validly timer based on the received message; performing a cellreselection evaluation using the first cell reselection priorities; andon a condition that the validity timer expires, deleting the first cellreselection priorities, applying second cell reselection prioritiesassigned to a second plurality of frequencies, and performing a cellreselection evaluation using the second cell reselection priorities. 2.The method according to claim 1, wherein the first cell reselectionpriorities are associated with a first plurality of cells, and thesecond cell reselection priorities are associated with a secondplurality of cells.
 3. The method according to claim 1, wherein thefirst cell reselection priorities are deleted on a condition that thetimer expires without the WTRU reselecting to a cell.
 4. The methodaccording to claim 1, further comprising: on a condition that the timerexpires, overwriting the first cell reselection priorities with thesecond cell reselection priorities.
 5. The method according to claim 1,further comprising: on a condition that the timer expires, reading thesecond cell reselection priorities from broadcast system information andoverwriting the first cell reselection priorities with the read secondcell reselection priorities.
 6. The method according to claim 1, furthercomprising: determining whether the message is provided via dedicatedsignaling, and on a condition the message is provided via the dedicatedsignaling, ignoring existing cell reselection priorities and performingthe cell reselection evaluation using the first cell reselectionpriorities.
 7. The method according to claim 1, wherein the second cellreselection priorities are obtained by reading system information. 8.The method according to claim 1, wherein the first cell selectionpriorities are received via dedicated signaling.
 9. The method accordingto claim 1, further comprising: on a condition that third cellreselection priorities assigned to a third plurality of frequencies havebeen received via dedicated signaling, applying the third cellreselection priorities for performing a cell reselection evaluation. 10.The method according to claim 9, wherein the third cell reselectionpriorities are received while the validity timer is not expired.
 11. Themethod of claim 1, wherein: during cell reselection, on a condition thata detected cell is a closed subscriber group (CSG) cell, camping, by theWTRU, on the detected cell only if a CSG indicator of the cell is on awhite list, and on a condition that the detected cell is a hybrid CSGcell, camping, by the WTRU, on the cell regardless of whether the CSGindicator of the detected cell is on the white list.
 12. The methodaccording to claim 1, wherein: the message is received via dedicatedsignaling and includes dedicated cell reselection priorities as thefirst cell reselection priorities, and the second cell reselectionpriorities are received in broadcast system information.
 13. A wirelesstransmit/receive unit (WTRU) comprising: a receiver and a processorconfigured to receive a message including first cell reselectionpriorities assigned to a first plurality of frequencies and a validitytimer associated with the first cell reselection priorities, wherein thevalidity timer indicates a length of time the first cell reselectionpriorities are valid; the processor is further configured to start thevalidity timer in response to the received message; the processor isfurther configured to perform a cell reselection evaluation using thefirst cell reselection priorities; and the processor is furtherconfigured, on a condition that the validity timer expires, to deletethe first cell reselection priorities, apply second cell reselectionpriorities assigned to a second plurality of frequencies, and perform acell reselection evaluation using the second cell reselectionpriorities.
 14. The WTRU according to claim 13, wherein the first cellreselection priorities are associated with a first plurality of cells,and the second cell reselection priorities are associated with a secondplurality of cells.
 15. The WTRU according to claim 13, wherein theprocessor is configured to delete the first cell reselection prioritieson a condition that the timer expires without the WTRU reselecting to acell.
 16. The WTRU according to claim 13, wherein the processor isconfigured, on a condition that the timer expires, to overwrite thefirst cell reselection priorities with the second cell reselectionpriorities.
 17. The WTRU according to claim 13, wherein, on a conditionthat the timer expires, the receiver is configured to read the secondcell reselection priorities from broadcast system information and theprocessor is configured to overwrite the first cell reselectionpriorities with the read second cell reselection priorities.
 18. TheWTRU according to claim 12, wherein the processor is configured todetermine whether the message is provided via dedicated signaling, and,on a condition the message is provided via the dedicated signaling, toignore existing cell reselection priorities and perform the cellreselection evaluation using the first cell reselection priorities. 19.The WTRU according to claim 13, wherein the second cell reselectionpriorities are obtained from system information.
 20. The WTRU accordingto claim 13, wherein the first cell selection priorities are receivedvia dedicated signaling.
 21. The WTRU according to claim 13, wherein:the processor is further configured, on a condition that third cellreselection priorities assigned to a third plurality of frequencies havebeen received via dedicated signaling, to apply the third cellreselection priorities for a cell reselection evaluation.
 22. The WTRUof claim 21, wherein the third cell reselection priorities are receivedwhile the validity timer is not expired.
 23. The WTRU of claim 13,wherein: the processor is further configured during cell reselection, ona condition that a detected cell is a closed subscriber group (CSG)cell, to camp on the detected cell only if a CSG indicator of the cellis on a white list, and, on a condition that the detected cell is ahybrid CSG cell, to camp on the cell regardless of whether the CSGindicator of the detected cell is on the white list.
 24. The WTRUaccording to claim 13, wherein: the message is received via dedicatedsignaling and includes dedicated cell reselection priorities as thefirst cell reselection priorities, and the second cell reselectionpriorities are received in broadcast system information.